To demonstrate the memoization, we can use an executable Kotlin script like this:

    #!/usr/bin/env kotlin -Xjvm-default=all -cp build/jam-0.9.jar

    interface FibonacciExample : Project {
        fun fib(x : Long) : Long = if (x < 2) x else fib(x - 1) + fib(x - 2)

        fun demo() {
            println("fib(10) = ${fib(10)}")
        }
    }

    Project.run(FibonacciExample::class.java, FibonacciExample::demo, args)

  % ./fibonacci.kts
  [compute] demo
  [compute]   fib 10
  [compute]     fib 9
  [compute]       fib 8
  [compute]         fib 7
  [compute]           fib 6
  [compute]             fib 5
  [compute]               fib 4
  [compute]                 fib 3
  [compute]                   fib 2
  [compute]                     fib 1
  [compute]                     fib 0
  [current]                   fib 1
  [current]                 fib 2
  [current]               fib 3
  [current]             fib 4
  [current]           fib 5
  [current]         fib 6
  [current]       fib 7
  [current]     fib 8
  fib(10) = 55

When the script completes the cache is saved to a local file. If we run the same script again, the result is ready to go:

  % ./fibonacci.kts
  [compute] demo
  [current]   fib 10
  fib(10) = 55